Because of superiorities in that, for example, an omni-directional wide illumination range is obtained and high antiglare effects are obtained, there are increasing demands for a balloon-type illumination device not only as projectors used in outdoor illumination in a construction site and the like but also as illumination devices for both outdoor and indoor various uses.
The conventional balloon-type illumination device includes a balloon that can inflate with the air pressure. A light source and a blower for inflating the balloon are disposed on the inside of the balloon.
As the light source of the balloon-type illumination device, in general, a discharge lamp such as an HID lamp is used. Electric power supplied from a generator or a commercial power supply is supplied to the discharge lamp via a ballast.
The ballast stabilizes the power supply power before supplying the same to the discharge lamp. A ballast called copper iron ballast mainly configured from a choke coil obtained by winding a copper wire around an iron core and a ballast called electronic ballast obtained by converting the copper iron ballast into an electronic form using an inverter and a thyristor control circuit are used.
The conventional balloon-type illumination device includes a holding part in the center of the balloon. The discharge lamp, the blower, and the ballast are disposed in the holding part on the inside of the balloon (see Patent Document 1 below).